“People can get an irregular heart rhythm after bingeing,” explains Dr. Peter Counihan, an associate professor at the University of Pittsburgh Medical Center’s Cardiovascular Institute. “It’s from the toxic effect of alcohol on the heart’s electrical system.”

The biggest culprit may be not how much people are drinking but the pattern they fall into when they’re doing it, suggests a new study published this week in the British Medical Journal.

The new research shows that occasional heavy drinking may be worse for your heart than drinking smaller amounts more frequently, perhaps upping the risk of heart attacks and deaths.

The study compared 2,405 men from Ireland, where people tend to drink heavily during weekend binges — perhaps five or more drinks a day — to 7,373 men from France, where alcohol tends to be consumed in smaller amounts but on a daily basis — usually wine with meals.

The researchers found that while the Irish actually consumed less overall alcohol — an average of 14 glasses a week vs. 21 a week for the French — the Irish tended to knock theirs back all at once over the course of the weekend. The French, on the other hand, spread them out over the course of a week, averaging three a day.

The international team of researchers focused on men from those two countries because earlier studies had shown that the Irish have a much higher rate of death from heart disease than the French. The researchers suspected that drinking patterns might be key to that difference.

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Binge drinkers have twice the risk
After accounting for factors such as age, blood pressure, cholesterol levels and Body Mass Index, the researchers determined that those who drank heavily, but irregularly, had twice the risk of heart attack and/or death as regular drinkers.

As for the long term effects of Irish and French patterns of alcohol consumption, experts suggest several factors might be coming into play. First, there is the impact of moderate drinking on lipids, says Dr. Nehal Mehta, director of the University of Pennsylvania’s Inflammatory Risk Clinic, Preventive Cardiology. The theory is that moderate levels of alcohol stimulate the liver to produce more HDL, the good kind of cholesterol, Mehta explains.

Beyond that, there's the effect of alcohol on blood pressure, says Counihan, the University of Pittsburgh professor. Binge drinking has been associated with spiking blood pressure levels.

But there may be other factors related to drinking patterns that help explain the differences between the French and the Irish, experts say.

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People in Ireland are more likely to consume alcohol in pubs, where closing times may spark higher — and more stressful — consumption. “So, you’re on a clock, if you like, and there’s a sort of peer pressure to consume large quantities in a short time,” says Counihan. “When the last call comes, you’ll see two or three drinks stacked up in front of people like flights coming in to land before the bar shuts down.”

In contrast, the French usually drink wine during dinner, often at home in a relaxed social setting. That may lead to more calming effect, Counihan says.

Ultimately, though, the results from the new study might be explained in part by differences in diet and genetics, says Mehta. Until more studies are done, we won’t know for sure, he adds.

In the meantime, experts agree, it might make sense to toast the season more like the French than the Irish.